Transcription initiation from a poly(dA) tract.
The mammalian ME1 gene encodes a non-tissue-specific, helix-loop-helix transcription factor that is enriched in morphogenetically active regions during development. Regulation of mouse ME1 gene expression is controlled by a novel initiator (ME1 Inr) that promotes transcription from the center of a 13 bp poly(dA) tract. We show here that the ME1 Inr autonomously directs initiation from the poly(dA) tract both in vitro and in vivo. This transcription was dependent upon two protein complexes; MBPalpha, which associated directly with the poly(dA) tract, and MBPbeta, which introduced an approximately 60 degrees bend immediately downstream of the poly(dA) tract. The MBPalpha and MBPbeta binding sites were strikingly conserved in homologous DNA from several mammalian species and the frog Xenopus laevis. These results suggest that the ME1 Inr constitutes a robust nucleation site that promotes transcription initiation in the absence of conventional promoter elements.
Shain
D H
DH
Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA. dshain@mendel.berkeley.edu
Zuber
M X
MX
Neuman
T
T
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011061:Poly A / Q000235:genetics*; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D029867:Xenopus Proteins; D014982:Xenopus laevis
D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D011061:Poly A; D014157:Transcription Factors; D029867:Xenopus Proteins; C489533:TCF12 protein, Xenopus; C489532:Tcf12 protein, mouse; C073366:TCF12 protein, human; C015465:poly(dA)